1. Field of the Invention
The invention is generally related to orthopedic braces and is specifically related to an ankle foot orthoses for drop foot and related ankle and foot conditions.
2. Description of the Prior Art
Drop foot and related conditions resulting from a paralysis or weakness of dorsi flexion muscles is often a condition experienced by stroke victims and can be brought on by other trauma, injuries and pathologies to the leg, foot and ankle, as well. Over the years, orthopedic braces have been developed to correct the condition, permitting a patient to walk and function in a relatively normal manner. Conventional braces used to correct drop foot conditions control and support the foot, but generally restrict motion about the ankle. The early braces were made of metal and included two solid bars which were placed on either side of the foot and extended upwardly along the inside and outside of the leg to a point below the knee. The upper end of the metal brace was then secured about the leg by use of a strap. The lower end of the metal brace was secured to a modified shoe and held the shoe in a generally horizontal position for supporting the foot.
The earliest braces of this type supported the shoe in a rigid position. This permitted the patient to walk and function in a generally normal manner with the foot rigidly held in place. Further developments incorporated a brace using the metal side members which fit inside the shoe and had a platform or base for supporting the foot. The base was often spring biased, permitting minimal flexing of the foot when walking, creating a more natural movement of the foot relative to the ankle and leg.
While these braces were functionally acceptable, the use of the metal side bars often created discomfort, were cosmetically unattractive, heavy and required the use of either modified or customized shoes in order to permit the brace to be attached to and properly support the foot.
With the advent of plastics, molded orthopedic braces became available. A molded orthopedic brace for foot drop was developed and was generally L-shaped in configuration, having a posterior support adapted to be placed against the back of the leg. The posterior support extended from a point below the knee to the heel of the patient, and included a contoured lower element which conformed to the bottom or plantar surface of the foot. The foot support base extended outwardly to the sides of the foot and forward from the heel toward the toes. The posterior brace was made of a unitary molded construction and generally held the foot in a rigid position. Because of the elevation of the foot by placing the brace behind the heel, and under the foot the patient was required to wear an enlarged or modified shoe in order to place the brace inside the shoe.
The plastic brace was also available in an articulating construction, wherein the foot base portion was a separate member hingedly connected to the posterior leg support. As with the earlier metal braces, the hinge was spring biased, to create a dynamic hinge permitting limited movement of the foot and ankle relative to the leg to simulate ankle movement during walking and other activities. An example of a hinged, articulated plastic orthotic brace is manufactured by Gaffney Technology of Hillsborough, Oreg.
The type of brace applied often depends on the severity of the condition and the patient's ability to function with an articulated brace or, where required, a rigid brace. Over the years, both the metal and plastic articulated and non-articulated braces have been incorporated as standard braces to be applied to correct for foot drop condition, with the specific brace being selected based on condition and on the patient's abilities.
While the posterior plastic braces provided some advantages over earlier metal braces and were cosmetically more desirable, the support of the foot from behind the heel is unnatural since the ankle muscular structure and tendons generally support the foot at the dorsal area. This was particularly true when the plastic posterior brace was allowed to articulate. The plastic posterior brace hinges the foot relative to the leg behind the heel rather than in front of the heel. Further, both the metal and plastic braces required the use of modified or in the least, enlarged shoes, generally making the condition and the brace obvious to even the most casual observer.